Some people are very careful to say Hashem or Elokim when singing a song with one of G-d's names in it so as not to use His name in vain (related question), but I have also been told this is unnecessary since these songs are equivalent to prayer.

If you shouldn't pronounce them, why did the authors put them in explicitly?

If there's no problem with pronouncing them, then how does repeating the words (for example, in the chorus) affect that? I mean, now that you're saying the words simply to fit in with the melody does that make pronouncing them in vain?

Both. Repeating Hashem's name definitely seems problematic, and changing the words of a verse or stanza which contains His name might also change its status from a prayer/Torah study to just singing.
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Michael SandlerOct 31 '11 at 8:02

2 Answers
2

Rambam (Sh'vuos 12:9) rules that one who uses Hashem's Name in a
meaningless oath or a an unwarranted blessing violates the Torah
prohibition to use His Name in vain. One who utters His Name without a
purpose transgresses the lower level, Torah commandment to fear His
Name (ibid.:11).In the latter case, the Rambam instructs one to
rectify an improper utterance of the Name by adding words of praise of
Hashem.

As the aforementioned Rambam hinted, it is likewise permissible to use
Hashem's Name to praise Him, including in Shabbat zemiros and other
liturgy. Indeed, some (incl. Rav Sh. Z. Orbach) pronounce the Names
normally. (The rhyming in some zemirot indicates that the liturgist
also did so.) However, many have the custom to alter the Names (Nefesh
HaRav, pg. 160 reports that Rav Soloveitchik did not utter the Names
in zemirot). The explanation of this custom is apparently that we are
concerned that we will not be in the proper frame of mind (B'tzel
Hachuchma IV, 52) or may stop in the middle of a phrase (see Igrot
Moshe, ibid.) or otherwise disgrace the Name. [Ed. or overly repeat
phrases in singing the Z'mirot.]

In practice, one can choose either to pronounce normally or change
Hashem's Names when reading Torah texts, saying informal prayers, or
singing zemirot. When studying b'rachot, he must change the Names;
when reading a whole pasuk, it is proper to pronounce the Names
accurately.

The Sefer Divre Shalom WeEmet on the Minhagim of North Africa writes that one should sing songs with Hashem's name. For the second part of the question, I heard the Baba Sali said not to repeat Hashem's name over and over but only say it once.